Treatment of hydrocarbons



' at... June 12, 194 s TREATMENT or mnpoeanoms,

- wma A. rm-mu, Beacon, N. Y., aslignor, s, mesne assignments, to The Texas Company, New York, N. Y., a corporation of Delaware a No Draidng. Application March 1a, m,

, ,seriem zozhsr e Claims ('01. 196-52) This invention relates to the catalytic dehydrogenation and cyclization of hydrocarbons.

More particularly, the invention has to do with the dehydrogenation of normally gaseous hydrocarbons, and the dehydrogenation and cyclization oi normally liquid hydrocarbons in the presence.

of a specialcatalyst under conditions of operation such that oleilns or olefins and aromatic hydrocarbons-are formed depending upon the hydrocarbons charged.

Inthe treatment of normally gaseous hydrocarbons, imaccordance with the invention, hydro carbons of two to tour carbon atoms, and prefer-, ably those of three and four carbon atoms, such as propane and butanes, may betreated. .By

"splitting of! two hydrogen atoms, these hydrocarbons may be converted into oleflns.

The normally liquid hydrocarbons contemplated for treatmentmay be gasoline or naphtha hydrocarbons and preferably hydrocarbons oi five to twelve carbon atoms. straight chain character, by splitting off hydrogen, may be converted into oleflns. Saturated also be converted into cyclic olefins or aromatics by splitting of! hydrogen. Also straight chain hydrocarbons oi. six to twelve carbon atoms may be dehydrogenated and cyclized into aromatic hydrocarbons, such as benzene or homologs thereof. Mixtures of hydrocarbons, such as gasoline or naphtha or relatively pure hydrocarbons, such as Cs, Cs, C1 or Cs compounds, may be treated to produce products of improved antiknock value for use in the manufacture of gasoline.

' The catalysts which are used for the abov purposes are specially prepared products obtained by treating natural or artificial zeolites such as Permutite r Doucil'. The zeolites are hydrous silicates comprising about equal molecular propor- .tions of an alkali metal oxide and aluminum oxide with varying proportions of silica and water. The alkali metal is replaceable'by other metals and advantage is taken-of this'characteristic in the preparation of thepresent catalyst. It is preferable to use a highly absorptive material which may be obtained artiflcially'or by acid treatment of natural or artificially prepared zeolites. The ratio of alkali to aluminum in such products may be about 1:1 or less. The alkali in these materials is replaced by a metal or the fourth, fifth and sixth group of the periodic system and preferably a'metal-selected from the. group consisting of the metals oi the lefthand columns. of groups IV, V and VI of the periodic table. Particular metals contemplated are titanium, zirconium, hafnium, thorium. vanadium, columbium, tantalum, chromium, molybdenum, tungsten and uranium. If desired, two or more of the above metals may be used.

In the preparation of the catalyst, the .zeolite is digested, for example, by boiling with about of a soluble salt of the desired metal such as the sulfate, nitrate or chloride, in a dilute water solution. The water solution is then drained of! 10 and the catalyst washed tree of soluble salts with water. The zeolite" in granular form is dried at about 500 C. before use. The product may be used in granular form or be pelletted into-pellets of about ,4 to 10 mesh.

16 The catalyst may be used in any,'.wel1 known or preferred type of apparatus, such as a tube and chamber, or in heated tubular type or equipment,

comprising two or more tubes or chambers connected in series or parallel. The oil is preheated 20 and passed in the vapor phase through the cat- Such hydrocarbons of alyst and the treated vapors separated in the conventional manner. The catalyst in time may-deteriorate in eflciency due-to carbon deposits and cyclic hydrocarbons, such asnaphthenes, may

itis advantageous to intermittently regenerate the catalyst by burning oil! the carbon. The regeneration may take place without interrupting the operation by using multiple catalyst chambers and cutting out the chamber for regeneration while others are-in use. 1

When using the above, catalyst for the purpose described, elevated temperatures of about 400 to 800 C. are required although temperatures up to 700' C. may be-used. Ordinarily temperatures of about 450 to 575 C. are suitable. At these temperatures-a time of reaction of between about v10 to '50 seconds and preferably around 20 seconds is suitable.

In some cases it is advantageous to use a substantial pressure of hydrogen for the purpose of 40 increasing the life of a catalyst, preventing carbon formation, and suppressing side reactions, such as cracking. It is contemplated, thereiore,. that when treating the normally liquid hydrocarbons particularly a substantial hydrogen pressure, may 7 be used by either introducing extraneous hydrosea. or by separating the gases produced in the operation and recycling them with the charge through the reaction zone. The hydrogen pres-fsure may vary somewhat with the type of hydrocarbon treated. but ordinarily hydrogen pressures of about! to 10 atmospheres aresatisiactory.

. As an example of the invention, normal heptaneis contacted ata temperature of around 575 C., at substantially atmospheric pressure,

and during a reaction time of about 20 seconds with a zeolite in which the alkali metal has been replaced. by molybdenum. A high yield of toluone is ob ained.

As a urther example ci invention, a pctroleum naphtha of about 10 octane number is 6 contacted at substantially atmospheric pressure,

at a temperature oi about 550 C. and during a reaction time of about 20 seconds with a oeolite (I i which the alkali metal had been replaced with zirconium. A yield of about 90% .0: a product 10 having an antiknock value oi about 55 is obtained.

Obviously many modifications and variations of the invention, as hereinbeiore set forth. may be made without departing from the spirit and i5 scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

' I claim:

1. A process for the dehydrogenation and cy 20 clization of gasoline hydrocarbons which comprises passing the hydrocarbons at temperatures of about 450 to 575 C. over granules of a solid catalyst comprising a zeolite in which the alkala metals have been replaced by a metal selected 25 from the group consisting of metals of the left hand column of group VI 0! the periodic system. 2. A process according to claim 1 in which the operation is carried out under a hydrogen presa sure of about 4 to 10 atmospheres.

3. A process for the production of aromatic hya,sve,oc7

drocarbons from straight chain-ah ydrocarb'ons of 6 to 12 carbon atoms which comprises subjecting the hydrocarbons in the vapor phase to the action of a 'zeolite catalyst at temperatures '01 about 400", to 600 C., said catalyst obtained by replacing the alkali metals of a zeolite with a metal selected from the group consisting of the metals of the left hand column 01' gro p VI f the Periodic system.

4. A process for reforming gasoline hydrocarbone which comprises passing the hydrocarbons in vapor phase at temperatures of about 400 'to 700 C. over a zeolite catalyst in which alkali metal or the zeolite has been replaced by a metal selected from the group consisting of metals of the left-hand column of group VI of the periodic system. t

5. A process for reforming gasoline hydrocarbone which comprises passing the hydrocarbons together with a substantial amount of hydrogen the left-hand column of group VI of the periodic system.

6. A process according to claim 5 in which the hydrogen is provided by recycling hydrogen-containing gases produced in the operation.

' wrnus A. YARNALn' 

